Efficient Energy Transfer for Near-Perfect Quantum Efficiency and Thermal Stability
Zheng Lu1,2, Dashuai Sun2, Sida Shen2
1School of Rare Earths, University of Science and Technology of China, Hefei 230026, P. R. China.
Abstract:
The pursuit of high-quality phosphors exhibiting swift response to near-ultraviolet (n-UV) excitation, elevated quantum efficiency (QE), superior thermal stability, and impeccable light quality has been a focal point of investigation. In this research, we synthesized a novel K2La2B2O7:Ce3+,Tb3+ (KLBO:Ce3+,Tb3+) color-tunable phosphor that meets these requirements. KLBO:Ce3+ can be stimulated efficiently by the n-UV light and shows an intense blue emission centered at 437 nm. Notably, KLBO:0.04Ce3+ exhibits exceptional internal QE (IQE = 94%) and outstanding thermal stability (I423 K/I303 K = 88%). Optimization of doping compositions enables efficient Ce3+ → Tb3+ energy transfer, resulting in substantial enhancements in QE and thermal stability. Specifically, KLBO:0.04Ce3+,0.28Tb3+ achieves an IQE of 98% and a thermal stability of 97%, higher than those of most phosphors of the same type. White light-emitting diodes fabricated using phosphor samples emit warm white light characterized by high Ra (Ra = 96.6 and 93.4) and low CCT (CCT = 4886 and 4400 K). This study underscores the feasibility of enhancing phosphor QE and thermal stability through energy transfer mechanisms.
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